BC:CM=CK:KM=BK:CK
BC=2CM
BC:CM=2
CK:KM=2 ⇒ [b]CK=2KM[/b]
BK:CK=2 ⇒[b] BK=2CK[/b]
S_( Δ BKM)=12
S_( Δ BKM)=(1/2)*BK*CK=(1/2)*2CK*CK
CK^2=12
[b]CK=2KM[/b] ⇒ KM=(1/2)CK
[b]S_( Δ CKM)[/b]=(1/2)*KM*CK=(1/2)*(1/2)*CK*CK=(1/4)CK^2=[b]3[/b]
S_( Δ BCM)=12+3=15
S_( Δ BCM)=(1/4)S_(квадрата)
S_(квадрата)=[red][b]60[/b][/red]